using System;

namespace Org.BouncyCastle.Asn1.X509
{
	/**
	 * <code>UserNotice</code> class, used in
	 * <code>CertificatePolicies</code> X509 extensions (in policy
	 * qualifiers).
	 * <pre>
	 * UserNotice ::= Sequence {
	 *      noticeRef        NoticeReference OPTIONAL,
	 *      explicitText     DisplayText OPTIONAL}
	 *
	 * </pre>
	 *
	 * @see PolicyQualifierId
	 * @see PolicyInformation
	 */
	public class UserNotice
		: Asn1Encodable
	{
		internal NoticeReference	noticeRef;
		internal DisplayText		explicitText;

		/**
		 * Creates a new <code>UserNotice</code> instance.
		 *
		 * @param noticeRef a <code>NoticeReference</code> value
		 * @param explicitText a <code>DisplayText</code> value
		 */
		public UserNotice(
			NoticeReference	noticeRef,
			DisplayText		explicitText)
		{
			this.noticeRef = noticeRef;
			this.explicitText = explicitText;
		}

		/**
		 * Creates a new <code>UserNotice</code> instance.
		 *
		 * @param noticeRef a <code>NoticeReference</code> value
		 * @param str the explicitText field as a string.
		 */
		public UserNotice(
			NoticeReference	noticeRef,
			string			str)
		{
			this.noticeRef = noticeRef;
			this.explicitText = new DisplayText(str);
		}

		/**
		 * Creates a new <code>UserNotice</code> instance.
		 * <p>Useful from reconstructing a <code>UserNotice</code> instance
		 * from its encodable/encoded form.
		 *
		 * @param as an <code>ASN1Sequence</code> value obtained from either
		 * calling @{link toASN1Object()} for a <code>UserNotice</code>
		 * instance or from parsing it from a DER-encoded stream.</p>
		 */
		public UserNotice(
			Asn1Sequence seq)
		{
			if (seq.Count == 2)
			{
				noticeRef = NoticeReference.GetInstance(seq[0]);
				explicitText = DisplayText.GetInstance(seq[1]);
			}
			else if (seq.Count == 1)
			{
				if (seq[0].ToAsn1Object() is Asn1Sequence)
				{
					noticeRef = NoticeReference.GetInstance(seq[0]);
				}
				else
				{
					explicitText = DisplayText.GetInstance(seq[0]);
				}
			}
			else
			{
				throw new ArgumentException("Bad sequence size: " + seq.Count);
			}
		}

		public override Asn1Object ToAsn1Object()
		{
			Asn1EncodableVector av = new Asn1EncodableVector();

			if (noticeRef != null)
			{
				av.Add(noticeRef);
			}

			if (explicitText != null)
			{
				av.Add(explicitText);
			}

			return new DerSequence(av);
		}
	}
}
